I have a older year model 302 and when it warms up the oil pressure drops dramatically. Is there a quick fix in a oil additive such as dura lube, slick 50,etc. I know the oil pickup screen is good and the oil is fresh 20w50. After warm up I only show 25 Lbs. pressure going down the highway on my aftermarket mechanical gauge.

 

The main cause of low oil presure in older engines, is that the rod and main bearings are worn and allowing excessives oil leaks inside the engine, there is not fix it in a can, but you can up your oil presure slightly with oil additives like STP. What they do is thicken the oil up. You can also get the same result by using straight 40Wt oil. Additives like dura lube, Slick 50 are PTF (tethlon) coathings, that help prevent engine wear, they do nothing for engines that are already worn,

Dave